Fix calculating mwv bitmasks with field arrays

Author: burrbull

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 
 ## [Unreleased]
 
+- Fix calculating `modifiedWriteValues` bitmasks with field arrays
 - Fix building without `yaml` feature
 - Compatibility with `riscv` 0.12 and `riscv-rt` 0.13
 - Add `riscv_config` section in `settings.yaml`

src/generate/register.rs

@@ -1343,15 +1343,23 @@ pub fn fields(
             }
 
             // Update register modify bit masks
-            let bitmask = (u64::MAX >> (64 - width)) << offset;
-            use ModifiedWriteValues::*;
-            match mwv {
-                Modify | Set | Clear => {}
-                OneToSet | OneToClear | OneToToggle => {
-                    one_to_modify_fields_bitmap |= bitmask;
-                }
-                ZeroToClear | ZeroToSet | ZeroToToggle => {
-                    zero_to_modify_fields_bitmap |= bitmask;
+            let offsets = match f {
+                MaybeArray::Array(info, dim) => (0..dim.dim)
+                    .map(|i| i * dim.dim_increment + info.bit_offset())
+                    .collect(),
+                MaybeArray::Single(info) => vec![info.bit_offset()],
+            };
+            for o in offsets {
+                let bitmask = (u64::MAX >> (64 - width)) << o;
+                use ModifiedWriteValues::*;
+                match mwv {
+                    Modify | Set | Clear => {}
+                    OneToSet | OneToClear | OneToToggle => {
+                        one_to_modify_fields_bitmap |= bitmask;
+                    }
+                    ZeroToClear | ZeroToSet | ZeroToToggle => {
+                        zero_to_modify_fields_bitmap |= bitmask;
+                    }
                 }
             }
         }